The present invention relates to differential-temperature-sensitive devices. The invention is particularly useful for actuating an electrical switch in response to a temperature-differential, and is therefore described below with respect to such an application.
There are many applications for differential-temperature-sensitive switches. One application is in a solar heating system, wherein a pump is actuated to pump hot water from the solar collector to the hot water storage tank, only when the water in the solar collector has been heated to a predetermined temperature differential with respect to the water in the water storage tank. Heretofore, such differential-temperature-sensitive devices have generally included electrical circuitry for measuring the temperature differential. Mechanical-type differential-temperature-sensitive devices have also been proposed, as illustrated for example in U.S. Pat. No. 2,549,054, but as a rule the known types have been of relatively complicated and costly construction. An object of the present invention is to provide a mechanical differential-temperature-sensitive device of simple and inexpensive construction for measuring the temperature differential and for actuating a controlled member, particularly an electrical switch, in response to the measured temperature differential.